According to prior arts, it has been known to obtain SOI including a handle substrate composed of a transparent and insulating substrate and called Silicon on Quartz (SOQ), Silicon on Glass (SOG) and Silicon on Sapphire (SOS). It has been also known an adhered wafer obtained by bonding a transparent wide-gap semiconductor, including GaN, ZnO, diamond, MN or the like, to a donor substrate such as silicon. SOQ, SOG, SOS and the like are expected for applications such as a projector and high frequency device due to the insulating property and transparency of the handle substrate. Further, the composite wafer, which is obtained by adhering a thin film of the wide-gap semiconductor to the handle substrate, is expected in applications such as a high performance laser and power device.
Such composite wafer for semiconductor is composed of the handle substrate and donor substrate, and the handle and donor substrates are generally made of single crystal materials. According to prior arts, it was generally performed a method of forming a silicon layer on a base substrate by epitaxial growth. It has recently developed a method of directly bonding them to contribute to the improvement of performance of a semiconductor device. That is, such handle and donor substrates are bonded through a bonding layer or an adhesive layer or directly bonded with each other.
On the other hand, it has been used a semiconductor (mainly silicon) as a substrate forming CMOS. As it is applied several hundreds of processing steps and equipments for them, it is decided a standard commonly applied to substrate wafers (SEMI: Semiconductor Equipment and Materials International).
Particularly, formation of CMOS transistors has been performed using an SOS (silicon on sapphire) substrate. As this wafer is produced by joining silicon with sapphire, it is required that the shape of silicon is in conformity with the shape of sapphire.
It is generally used a silicon wafer of plane orientation of <100>, and it is important to recognize the plane orientation for the matching with mask pattern. It is indicated in a method of “notch” according to the “SEMI standard, and the specification of the notch is defined (non-patent document 1).
Further, as the development of the bonding technique, it has been proposed various kinds of handle substrates made of materials, other than sapphire, such as quartz, glass and alumina (Patent documents 1, 2, 3 and 4).
Further, according to patent document 5, a cover wafer is made of a sintered body of yttria, ytterbium oxide, lanthanum oxide or ruthenium oxide free from both of silicon and aluminum, and the cover wafer is mounted on a substrate holder of a semiconductor production chamber to prevent generation of a silicon compound or aluminum compound. Here, a V-notch is formed in the cover wafer (0022).